Daron Wint, 35, of Lanham, Maryland, is accused of holding construction business owner Savvas Savopoulos and the others captive until he got $40,000 in cash, killing them and setting fire to their mansion, the U.S. Attorney’s Office in Washington D.C. said in a statement.

The indictment includes 12 counts of first-degree murder while armed with aggravating circumstances, as well as four counts of kidnapping, and one count each of burglary, extortion, arson and theft, the statement said.

The grand jury in the D.C. Superior Court found the murders were “especially heinous, atrocious or cruel,” the statement said.

Attorneys for Wint could not be immediately reached for comment, but his attorney, Natalie Lawson, said during his arraignment that the government’s case was “based on speculation and guesswork.”

Savopoulos, who owned a construction materials company; his wife, Amy, 47; son Phillip, 10; and housekeeper Veralicia Figueroa, 57, were held captive on the evening of May 13. Savopoulos had an aide deliver $40,000 in cash to the house the next day, the court document said.

The bodies were found on May 14 inside the Savopoulos mansion in an upscale neighborhood near the official residence of Vice President Joseph Biden. The house had been set on fire.

Police said Wint had worked for Savopoulos’ company, American Iron Works.

Wint was a passenger in a car that was traveling alongside a truck when he was arrested later that month. Police also arrested three men and two women in the vehicles, though Police Chief Cathy Lanier later told CNN the others were released.

Each of the 12 murder charges carries a maximum sentence of life imprisonment without the possibility of release, the statement said.